Question: #9: Answer A frequently used to express a level of certainty or near certainty. #15: Answer D also, referring to a past event. "The cake was eaten, and I saw her eat the cake." #20: Answer B also, to express not just a possibility (answer A), but a strong likelihood. #63: Answer C also, simple past. Answer A for testimony yet to be given -- future tense. #77: Answer B also. #83: Answer B is incorrect. Answer A is correct. The verb must agree with the subject "He" which is singular. "People" is instead the object of the prepositional phrase "of those people," and thus has no role in determining verb-tense.